Hi All, I have a barrel pond fountain. I have had it going for a couple of weeks, with plants and snails. I want to add some Mosquito fish now, but can't find any info on how many to buy. I have read that they need to have a 20 gallon container (which is what the fountain is), but no info on how many per 20 gallon container. Plus, I don't want 100's of baby fish either. Any advice would be appreciated.